diff --git a/tests/logging_callback_tests/test_prometheus_unit_tests.py b/tests/logging_callback_tests/test_prometheus_unit_tests.py
index d4ade14c0..e3bd6510a 100644
--- a/tests/logging_callback_tests/test_prometheus_unit_tests.py
+++ b/tests/logging_callback_tests/test_prometheus_unit_tests.py
@@ -1,3 +1,7 @@
+"""
+Unit tests for prometheus logging callback
+"""
+
 import io
 import os
 import sys